96 FOREST UTILIZATION 



A plant must be located : 



I. Close to water; water is not so much us'ed for motive 

 power as for the dissolution of the fibre in the washing 

 process. 

 II. Close to cheap wood supply ; wood must be plentiful and 

 uniform, of a long, straight fibre, readily interlacing and 

 white. Spruce is considered best, the price at river 

 fronts being about $3.50 per cord and at mill from $4.50 

 to $5.50. Cottonwoods and poplar are next in impor- 

 tance. Price at river fronts $2. Hemlock and- balsam 

 are mixed with spruce in a daily growing proportion. 

 Birch, beech and maple can be used only for wrapping 

 paper and cardboard, the fibre being short, brittle and 

 unbleachable. 

 The use of pine is handicapped by the expense of the 



removal of the rosin. 

 The Pacific spruces and cottonwoods may have a great 

 future. 

 III. Qose to cheap coal, since the coal consumption per pound 

 of paper amounts to 5/16 of a pound of coal. So much 

 coal is required for heating, drying and bleaching, that 

 all excepting 15% of the machinery can be driven free 

 of charge. 

 D. Process of manufacture. 



The manufacture is either purely mechanical (ground wood pulp) 

 or also chemical. In the latter case, distinguish between the 

 soda process, the sulphite process and the, sulphate process. 

 The electric process, though very promising, is still in early 

 infancy. 

 The principle of manufacture is : 



Grinding and. beating of wood in water until it forms a fluid pulp; 

 allowing water to run off leaving a matted stratum of wet fibre ; 

 bleaching ; drying ; pressing. 

 I. Ground wood fibre. 



(a) The wood is cut into bolts one foot long and five 



inches thick. The bark is removed, and the 

 knots are usually bored out. 



(b) The bolts are pressed against stone mill-wheels 



which turn slowly under constant influx of 

 water. Bolts must be ground in the direction of 

 the fibre. 



(c) The fluid pulp is carried through sieves retaining 



the long splinters, which are transferred to a 

 pulp engine for mechanical refining. 



(d) The fibre is ground a second time both in stamp- 



ers and rotary mills, 

 (e)- The fluid i.s separated according to fineness by 

 sieves of different mesh which allow the water 

 to run off. The filtered mass is taken up by 



